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Project No. JB-569 20 June 2006 Page 5 According to the proposed grading plan, as shown on Figure 2, the Lot 1 building pad will be near existing grade, the Lot 2 building pad will be cut and fill, and the Lot 3 building pad will be fill material. We do not recommend that the footings be founded partly on fill and partly on cut material. Therefore, to help reduce the potential for differential settlement, the on-site soils should be over-excavated, moisture-conditioned, and recompacted in the Lot 1 and Lot 2 foundation areas as recommended in the earthwork section of this report. Provided the earthwork recommendations are followed, it is our opinion that the proposed residences may be supported on a conventional foundation system established on compacted, engineered fill Proper drainage must be provided to prevent moisture from penetrating beneath foundations, concrete slabs-on-grade, and pavements. If moisture penetrates the soils beneath these areas, there could be some movement and resulting cracking/distress. Recommendations to help reduce the movement of the foundations and concrete slab-on-grade floors/flatwork are discussed in later sections of this report. 6.0 RECOMMENDATIONS 6.1 Earthwork 6.1.1 General As previously stated, final grading plans were not available during preparation of this report. We recommend that final grading plans be reviewed by our office prior to starting the grading operations. As previously discussed, the Lot 1 building pad will be near existing grade, the Lot 2 building pad will be cut and fill, and the Lot 3 building pad will be fill material. We do not recommend that the foundations be founded partly on fill and partly on cut material. To help reduce the potential for differential settlement, we recommend the foundation subgrade soils for Lot 1 and the Lot 2 cut areas be over-excavated a minimum of 2 feet below the proposed footing elevation for the foundation areas, moisture-conditioned, and recompacted in the foundation area and at least 5 feet beyond the structure and exterior flatwork/sidewalk areas in plan view, if practicable. Deeper sub-excavation may be required depending on soil conditions encountered during grading. Figure 8, Foundation Materials Under Building, presents the details for over-excavating and replacing the soil with compacted, engineered fill within the building limits. The existing undocumented fill should be excavated and recompacted as shown in Figure 9, Typical Buttress and Subdrain. Compaction recommendations are discussed in Section 6.1 .4 Fill Placement and Compaction. ~Korbmacher Engineering, Inc.